My feelings on the topic are different.
I felt like all the possible routes had a intention behind them.
I picture the example you used ("I also constantly took the track that *seemed* to head towards my objective only to run into a dead end with the objective just out of sight and was forced to back track all the way to the ambush I purposely skirted.") is the way you can enter the goblin camp from the mountain pass - if you do a large jump and then get down the cliffs via means of feather fall or misty step.
I do not think it demands too many ressources to go this route. Think of it: The alternative is passing (several) Goblin encounters, Big fights (unless you role well or use your tadpole). If you feel like the fight is too risky, you might just as well invest your spell slots in a route that comes at a calculatable cost. Really two spell slots are nothing compared to what you would likely use in the battles.
I'm not sure if that's the idea behind it, but once you got your one travel-spell-buffed character to the Goblin camp waypoint, you can just teleport the rest of your party there.
I felt a little lost when I thought I headed to my destination but ultimately didn't. But I feel like that's just what t is in real life, too. Somebody tells you there is a camp to the west? Does't mean heading straight west will be the direct route there. It also makes me discover so much more I would probably never check out if I knew where exactly a quest takes me. To me, that's exploration. I come across different quests, giving me the choice which one to follow first. If I realize there are encounters or other obstacles too difficult for me to face now, I can always search for another route - but the choice is mine, I may just as well try to break through the most direct route I find.
As for marking your map: I agree. But given prior Larian games made you able to do that, I assume this feature is simply not implemented in early access yet and is therefore still to come.
